A wide variety of modern devices utilize rechargeable batteries. These devices often have a power controller, which may be included in the battery or the device itself, that provides an estimate of the amount of energy in the battery during charging and discharging that is used to produce a power level display or reading. The maximum, minimum, and display changing power levels, i.e. power bars, for the power level display are either hard wired into the device or determined under a specific set of circumstances. Unfortunately, the charge capacity of a rechargeable battery changes over the lifetime of the battery. Thus, the power controller needs to be recalibrated from time to time to keep the power level display accurate. The power controller typically waits until the battery is completely discharged and then recharged in a single full cycle discharging/charging operation to set the new maximums, minimums and display levels. Doing so insures that the true maximum and minimum charge levels can be determined and displayed. Unfortunately, many users do not periodically fully discharge and recharge their device's batteries as recommended by battery manufacturers. This may lead to an unexpected loss of power when a power level display indicates that power remains or the consumer believing that the battery needs charging when in reality it still retains a sufficient charge for operation. Either situation can lead to a loss of consumer goodwill. Therefore, what is needed is a new and improved method and device for automatically recalibrating a power level display to insure its accuracy.